An automatic piloting system (PA) makes it possible to automatically accomplish a set of more or less complex activities that previously used to be carried out manually by the pilot. By advocating manoeuvres suited to the conditions and to the flight plan, it helps to lighten the pilot's load. The development and maintenance of such systems are complex and expensive since they depend not only on the technical specifications of the aircraft equipment but also on the operational customs and procedures of aircraft manufacturers. The maturity of the expression of the aircraft manufacturer's need, in terms of defining the behaviour of the PA, progresses during the course of the development of an aircraft. As long as the expression of the need has not come to an end, the design of an automatic piloting system is faced with numerous iterations of software development, sometimes up until in-flight trials and beyond commissioning into service. Moreover, the software of an automatic piloting system must be certified. The certification process consists in providing an organization with proofs related to the software development activities in order to obtain certification credits for all or part of the software. As the behaviour of the automatic piloting system depends on the specific need of an aircraft manufacturer, interfaced systems and aerodynamic parameters specific to the carrier, the software of an automatic piloting system must be modified or redeveloped for each particular aircraft.
The automatic piloting systems of the prior art which exhibit the characteristic of being developed specifically (without gaining certification credit from the previous developments) as a monolithic sequential code require iterations which are lengthy, expensive and uncertain in terms of timescale. Regular software updates may be necessary during development, and during the phase of commercial operations when the aircraft manufacturer requests modification or addition of new automatic piloting functions. Under the conditions of the prior art, any modification involves repeating all or part of the software certification process.